U.S. patent number 9,965,053 [Application Number 14/381,162] was granted by the patent office on 2018-05-08 for touchpen for capacitive touch panel and method of detecting a position of a touchpen.
This patent grant is currently assigned to Sony Corporation, Sony Mobile Communications Inc.. The grantee listed for this patent is SONY CORPORATION. Invention is credited to Alexander Hunt, Magnus Ola Johansson, Peter Ljung.
United States Patent |
9,965,053 |
Johansson , et al. |
May 8, 2018 |
Touchpen for capacitive touch panel and method of detecting a
position of a touchpen
Abstract
The disclosure relates to the technical field of capacitive
touch panels and discloses a touchpen which may be used in mobile
phones, computers and other devices with touch panels for writing
characters, letters and other symbols. In particular it relates to
a capacitive touchpen 10 for inputting information into an
electronic device 1 through touching of a capacitive touch panel
30, the capacitive pen comprising an elongated body member 11
comprising a conductive part 13 and a tip 12 disposed at one end of
the body member 11 having a contact surface 14 for contacting the
capacitive touch panel 30. The conductive part 13 is configured
such that the distortion of the touch panel's electrostatic field
caused by the conductive part 13 when changing the position of the
touchpen 10 in relation to the capacitive touch panel 30, when the
contact surface is kept in contact with the touch panel 30, is
sufficient to register a change in capacitance by the capacitive
touch panel 30. The disclosure further relates to methods for
detecting the position of a touch pen as well as to an electronic
device and a computer program.
Inventors: |
Johansson; Magnus Ola
(Dosjebro, SE), Ljung; Peter (Lund, SE),
Hunt; Alexander (Tygelsjo, SE) |
Applicant: |
Name |
City |
State |
Country |
Type |
SONY CORPORATION |
Minato-ku, Tokyo |
N/A |
JP |
|
|
Assignee: |
Sony Corporation (Tokyo,
JP)
Sony Mobile Communications Inc. (Tokyo, JP)
|
Family
ID: |
49817125 |
Appl.
No.: |
14/381,162 |
Filed: |
September 26, 2013 |
PCT
Filed: |
September 26, 2013 |
PCT No.: |
PCT/IB2013/002142 |
371(c)(1),(2),(4) Date: |
August 26, 2014 |
PCT
Pub. No.: |
WO2015/044701 |
PCT
Pub. Date: |
April 02, 2015 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20150293613 A1 |
Oct 15, 2015 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F
3/0446 (20190501); G06F 3/0442 (20190501); G06F
3/03545 (20130101) |
Current International
Class: |
G06F
3/0354 (20130101); G06F 3/044 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
International Search Report dated May 16, 2014, issued in
corresponding PCT application PCT/IB2013/002142, 11 pages. cited by
applicant .
Office Action from corresponding European Application No. 13810997,
dated Oct. 25, 2017, 9 pages. cited by applicant.
|
Primary Examiner: Sarma; Abhishek
Attorney, Agent or Firm: Tucker Ellis, LLP
Claims
The invention claimed is:
1. A passive capacitive touchpen for inputting information into an
electronic device through touching of a capacitive touch panel that
has capacitive sensors, the passive capacitive touchpen comprising:
an elongated body member comprising a conductive part; and a
conductive tip, disposed at one end of the elongated body member,
having a contact surface for contacting the capacitive touch panel,
wherein a size of an area on the capacitive touch panel touched by
the contact surface does not significantly change with changes in
orientation of the touchpen, wherein the conductive part is
longitudinally spaced apart from the conductive tip along the
elongated body member and radially larger than the contact surface,
wherein the conductive tip and conductive part are configured such
that, when the contact surface is kept in contact with the
capacitive touch panel and the orientation of the touchpen in
relation to the capacitive touch panel is changed, the conductive
tip and conductive part passively induce a distortion of an
electrostatic field of the capacitive touch panel sufficient to
register a change in capacitance directly measurable by the
capacitive sensors, the distortion of the electrostatic field
having a shape of distortion, wherein the shape of the distortion
indicates the orientation of the touchpen, wherein the conductive
tip is resiliently retractable into the elongated body member
toward the conductive part responsive to an application of a
contact pressure of the passive capacitive touchpen with the
capacitive touch panel, and wherein the conductive tip is
mechanically adjustable or interchangeable with another conductive
tip to change retraction reaction to contact pressure amount, the
distortion of the electrostatic field of the capacitive touch panel
being further controlled by the contact pressure amount and
retraction reaction of the conductive tip.
2. The passive capacitive touchpen according to claim 1, wherein
the conductive tip is thinner than the elongated body member.
3. The passive capacitive touchpen according to claim 1, wherein
the distance between the conductive part and the capacitive touch
panel is decreased by pushing the resilient retractable conductive
tip into the elongated body.
4. The passive capacitive touchpen according to claim 1, wherein
the conductive tip is held by an elastic member such that the
retraction depends on the contact pressure amount applied on the
conductive tip.
5. The passive capacitive touchpen according claim 1, wherein the
distance between the conductive part and the capacitive touch panel
is decreased by tilting the elongated body member to have a smaller
angle with the capacitive touch panel.
6. The passive capacitive touchpen according to claim 1, wherein
the conductive part is electrically coupled to the conductive
tip.
7. A method in an electronic device of inputting information into
the electronic device from a passive capacitive touchpen through
touching of a capacitive touch panel having capacitive sensors, the
passive capacitive touchpen having an elongated body member that
includes a conductive part, and a conductive tip, which is
resiliently retractable into the elongated body member toward the
conductive part responsive to an application of a contact pressure
of the passive capacitive touchpen with the capacitive touch panel,
disposed at one end of the elongated body member, the conductive
tip having a contact surface for contacting the capacitive touch
panel, and wherein the conductive tip is mechanically adjustable or
interchangeable with another conductive tip to change retraction
reaction to contact pressure amount, wherein a size of an area on
the capacitive touch panel touched by the contact surface does not
significantly change with changes in orientation of the touchpen,
and wherein the conductive part is longitudinally spaced apart from
the conductive tip along the elongated body member and radially
larger than the contact surface; the method comprising: detecting
contact of the conductive tip at the capacitive touch panel;
measuring a passively induced distortion of an electrostatic field
of the capacitive touch panel, caused by the conductive tip and the
conductive part, directly by the capacitive sensors, the distortion
of the electrostatic field having a shape of distortion controlled
by the contact pressure amount and retraction reaction of the
conductive tip; determining a change in orientation of the passive
capacitive touchpen in relation to the capacitive touch panel based
on the shape of the distortion of the electrostatic field of the
capacitive touch panel; and determining a change in contact
pressure of the passive capacitive touchpen with the capacitive
touch panel based on the distortion of the electrostatic field of
the capacitive touch panel.
8. The method of claim 7 wherein the change in orientation is
detected using a size of the distortion of the electrostatic field
of the capacitive touch panel.
9. The method of claim 7 wherein the change in orientation is
detected using an amplitude of the distortion of the electrostatic
field of the capacitive touch panel.
10. A passive capacitive touchpen for inputting information into an
electronic device through touching of a capacitive touch panel that
has capacitive sensors, the passive capacitive touchpen comprising:
an elongated body member comprising a conductive part; and a
conductive tip, disposed at one end of the elongated body member,
having a contact surface for contacting the capacitive touch panel,
wherein a size of an area on the capacitive touch panel touched by
the contact surface does not significantly change with changes in
orientation of the touchpen, wherein the conductive part is
longitudinally spaced apart from the conductive tip along the
elongated body member and radially larger than the contact surface,
wherein the conductive tip is resiliently retractable into the
elongated body member toward the conductive part responsive to an
application of a contact pressure of the passive capacitive
touchpen with the capacitive touch panel, and wherein the
conductive tip is mechanically adjustable or interchangeable with
another conductive tip to change retraction reaction to contact
pressure amount, whereby a distortion of an electrostatic field of
the capacitive touch panel is controlled by the contact pressure
amount and retraction reaction of the conductive tip.
Description
TECHNICAL FIELD
The disclosure relates to the technical field of capacitive touch
panels and discloses a touchpen which may be used in mobile phones,
computers and other devices with touch panels for writing
characters, letters and other symbols as well as for painting,
drawing, illustration, re-touching photos. In particular it relates
to a touchpen making it possible to detect the position, such as
tilt and distance, of the touchpen in relation to a touch panel.
The disclosure further relates to methods for detecting the
position of a touch pen as well as to an electronic device and a
computer program.
BACKGROUND
Touch panel devices that can be operated by an operator directly
touching a screen while images are displayed on the screen are
commonly known. Such touch panel devices are often used in a
portable information processing terminals such as a PDAs (Personal
Digital Assistants), cellular phone terminals, Smartphones, or the
like (hereafter called "electronic devices"). A touch panel device
has a touch panel to detect an object approaching the surface.
Types of touch panels include a resistor film method that detects
resistor value changes to a touched portion, a capacitance type
that detects capacitance changes to the touched portion, an
electromagnetic conduction method to detect the position of an body
with the electromagnetic energy of an body dedicated to emitting a
magnetic field, and so forth. Recently, use of capacitance-type
touch panels have increased, particularly in the cellular phone
terminal and Smartphone markets.
When touch sensitive mobile phones and PDA's were first introduced
the main input device was a pen. This changed when Smartphones were
introduced where all input was made with your fingers. With finger
input, capacitive touch sensors replaced other technologies (like
resistive sensors used for pen input) due to increased finger touch
sensitivity. Capacitive sensors allowed a lower finger pressure to
be detected compared with other technologies.
However, pen input are coming back with recent products. In recent
products the capacitive sensors are sometimes complemented, with
active pen technology. Active pens allow detection of pen pressure
and tilt which cannot be measured directly using capacitive
sensors. In these devices, tilt and pressure are e.g. measured by
the pen itself and sent to the phone through radio
communication.
Typically when drawing on a touch screen, the distance (assume
distance of pen tip from surface) is not used, but rather pressure
of the pen. Compare with a normal graphite pen. Pressure in current
capacitive touch solutions with passive pointers are artificially
calculated based on the size of the pointer. A large pointer size
is interpreted as much pressure and a small pointer is interpreted
as little pressure. When fingers are used as input means it is
actually possible to measure pressure indirectly. When the finger
is pressed harder against the surface, the size of the contact
surface, will increase which is detected by the sensor. There are
touchpens designed with a relatively large and soft pen tip (like a
finger) which allow pen pressure to be measured in the same way.
But when a pen is used for drawing or writing a small pen tip is
preferred to allow better visual feedback during drawing.
The sensitivity of capacitive sensors are also being improved which
allow almost any kind of passive pen to be used as input device, as
long as it is conductive. As an example an ordinary graphite pen
with a tip area of at least 1-2 mm may be used with current state
of the art technology, but then pen pressure or tilt cannot be
measured. Graphite is stiff and can not change footprint which
makes it difficult or even impossible to measure preassure with
this technology.
SUMMARY
This disclosure presents a solution where a passive pen on a
capacitive touch sensor can allow both pressure and tilt to be
measured without using the pointer size or only use it as a
complement. This allows the same functionality as an active pen
technology, but with no additional cost from dual touch sensor
solutions, i.e. touch screens having an additional solution for
handling pens.
According to one aspect the present disclosure relates to a
capacitive touchpen for inputting information into an electronic
device through touching of a capacitive touch panel. The capacitive
pen comprises an elongated body member comprising a conductive part
and a tip disposed at one end of the body member having a contact
surface for contacting the capacitive touch panel. The conductive
part is configured such that the distortion of the screen's
electrostatic field caused by the conductive part when changing the
position of the touchpen in relation to the capacitive touch panel,
when the contact surface is kept in contact with the touch panel,
is sufficient to register a change in capacitance by the capacitive
touch panel.
Thereby, the position of the pen may be detected, because the
conductive part will generate a capacitive foot print which depends
on the position, e.g. tilt, of the pen. In use the pen would of
course often be moving. However, at a certain moment, it is then
possible to detect both the touched point of the pen (x,y) and a
value or values corresponding to the position. The position may be
translated to e.g. tilt and/or pressure, depending on the design of
the pen, as will be shown in the embodiments below.
According to one aspect the tip is thinner than the elongated body
member. A thin tip enables drawing detailed patterns. According to
one aspect the tip is retractable. It is then possible to decrease
the distance between the conductive part of the body and the
capacitive touch panel is decreased by pushing the retractable tip
into the body.
According to one aspect the tip is held by an elastic member such
that the retraction depends on the pressure applied on the tip.
According to one aspect the distance between the conductive part
and the capacitive touch panel can be decreased by tilting the
body.
According to one aspect the tip is conductive. According to one
aspect the conductive part is electrically coupled to the tip.
Electrical coupling will increase the foot print of the conductive
part.
According to one aspect the disclosure relates to a method in an
electronic device of detecting the position of a touchpen used for
inputting information into the electronic device through touching
of a capacitive touch panel, the touchpen comprising an elongated
body member comprising a conductive part and a tip disposed at one
end of the body member. The method comprises detecting contact of
the tip at the capacitive touch panel, measuring a distortion of
the screen's electrostatic field and determining a change in
position of the touchpen in relation to the capacitive touch panel,
based on the distortion of the screen's electrostatic field caused
by the conductive part.
According to one aspect the change in position is detected using
the shape of the distortion of the screen's electrostatic field.
According to one aspect the change in position is detected using
the size of the distortion of the screen's electrostatic field.
According to one aspect the change in position is detected using
the amplitude of the distortion of the screen's electrostatic
field.
According to one aspect the disclosure relates to a wireless device
configured to execute the method described above.
According to one aspect the disclosure relates to a computer
program, comprising computer readable code which, when run on a
wireless network node in a cellular communication system, causes
the node to perform the method as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
The present technique will be more readily understood through the
study of the following detailed description of the
embodiments/aspects together with the accompanying drawings, of
which:
FIG. 1 illustrates inputting information in an electronic device
using a touchpen.
FIGS. 2a and 2b shows a schematic configuration of a
capacitance-type touch panel device.
FIG. 2c is a descriptive diagram schematically showing an expanded
view of a rectangular transparent electrode unit.
FIG. 3a-3b illustrates the touchpen according to one aspect of the
invention.
FIG. 4a-4c illustrates the touchpen according to one aspect of the
invention.
FIG. 5a-5b illustrates the touchpen according to one aspect of the
invention.
FIG. 6 discloses in a flowchart a method in an electronic device of
detecting the position of a touchpen used for inputting information
into the electronic device through touching of a capacitive touch
panel.
It should be added that the following description of the
embodiments is for illustration purposes only and should not be
interpreted as limiting the disclosure exclusively to these
embodiments/aspects.
DETAILED DESCRIPTION
Embodiments of the present invention will be described more fully
hereinafter with reference to the accompanying drawings, in which
embodiments of the invention are shown. This invention may,
however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein. Rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. Like reference signs refer
to like elements throughout.
Embodiments of the present invention will be exemplified using a
mobile communication device such as a mobile phone. However, it
should be appreciated that the invention is as such equally
applicable to electronic devices which have touch detection
capabilities. Examples of such devices may for instance be any type
of mobile phone, laptop (such as standard, ultra portables,
netbooks, and micro laptops) handheld computers, portable digital
assistants, tablet computers, gaming devices, accessories to mobile
phones, etc. However, for the sake of clarity and simplicity, the
embodiments outlined in this specification are exemplified with,
and related to, mobile phones only.
FIG. 1 illustrates inputting information in an electronic device 1
having a touch panel device 20 using a touchpen 10. Note that
according to the present embodiment, an example is given wherein
the touch panel device 20 is applied to the portable terminal 1,
but should not be limited to this.
FIG. 2 shows a schematic configuration of a capacitance-type touch
panel device 20. Note that FIG. 2a shows a diagram as seeing the
touch panel 30 from the front, and FIG. 2B shows a diagram as
seeing the touch panel 30 from the side.
FIG. 3 is a descriptive diagram schematically showing an expanded
view of a rectangular transparent electrode unit of the
capacitance-type touch panel 30. The touch panel device 20 has an
IC 21, touch panel 30, X-Y transparent electrode pattern unit 31,
flexible print substrate 34, sensor glass unit 36, and so forth.
The touch panel 30 is disposed so as to be layered over a display
(see FIG. 1).
The X-Y transparent electrode pattern unit 31 is formed on the
surface of the sensor glass unit 36 made up of e.g. a transparent
glass plate. For example, multiple rectangular transparent
electrode units 40X are arrayed in the X-direction and in multiple
rows, and multiple rectangular transparent electrode units 40Y are
arrayed in the Y-direction and in multiple rows.
The various rectangular transparent sensors or electrode units 40X
arrayed in the X-direction in multiple rows are connected with a
connecting unit between the various adjacent rectangular
transparent electrode units 40X. Similarly, the rectangular
transparent electrode units 40Y arrayed in the Y-direction in
multiple rows are connected with a connecting unit between the
various adjacent rectangular transparent electrode units 40Y. The
various connecting units to connect between the various adjacent
rectangular transparent electrode units 40X and the various
connecting units to connect between the various adjacent
rectangular transparent electrode units 40Y are each formed with a
transparent electrode.
Also, the various rectangular transparent electrode units 40X that
are on the outer most edges of the various rectangular transparent
electrode units 40X connected in flexible print substrate 34 via
the outer edge wiring pattern 43X. Similarly, the various
rectangular transparent electrode units 40Y that are on the outer
most edges of the various rectangular transparent electrode units
40Y are connected in an outer edge wiring pattern 43Y, and
connected in a wiring pattern of a flexible print substrate 34 via
the outer edge wiring pattern 43Y.
The IC 21 is mounted on the flexible print substrate 34, and is
connected to the outer edge wiring pattern 43X and outer edge
wiring pattern 43Y of the X-Y transparent electrode pattern unit 31
via the wiring pattern on the flexible print substrate 34. The IC
21 scans each of the various rectangular transparent electrode
units 40X in the X-direction and the various rectangular
transparent electrode units 40Y in the Y-direction of the X-Y
transparent electrode pattern unit 31, and detects changes in
capacitance in the X-direction and Y-direction. The coordinates
value and the capacitance detection values when the object such as
the finger of the user or a touchpen 10 nears the sensor surface of
the touch panel 30 and so forth are calculated by the changes in
the detected capacitance.
The format of the output of the touch panel device 20 varies
between different devices. According to one example the output
comprises the X and Y coordinates of a detected touch as well as a
Z value. The Z value corresponds to the pressure and corresponds to
the size and/or amplitude of the detected capacitance. Size in this
case refers to the number of sensors or electrodes 40X, 40Y
detecting change in capacitance. Amplitude corresponds to the value
of each sensor. The output may as well comprise the form or shape
of the detected capacitance.
Capacitive sensors can actually detect items above the surface of
the panel. A conductive material does not have to touch the panel
to change the capacitance, but the effect decreases fast relative
the distance from the screen. Typically objects a few millimetres
above the surface can be detected. With today's technology the
maximum distance can range from 5-20 mm but is expected to improve
in the future. A solution that allows pen input with a small tip
while still allows pressure to be detected use this property.
FIG. 3 discloses a passive capacitive touchpen 10 for inputting
information into an electronic device through touching of a
capacitive touch panel according to one aspect of the invention.
The pen comprises a body member or housing 11 and a pen tip or tip
12. The body member 11 has an elongated shape. The elongated body
member 11 comprises a conductive part. Hence, the body member 11 is
at least partly conductive, but it may as well be completely made
of a conductive material.
The tip 12 is disposed at one end of the body member 11. The tip 12
has a contact surface 14 for contacting the capacitive touch panel.
Different parts of the contact surface 14 may be in contact with
the touch panel depending on the tilt of the pen. According to one
aspect the pen tip 12 is conductive. The tip is typically thinner
than the elongated body member 11, meaning that it has a smaller
diameter d. The tip is typically smaller than the grid of the touch
panel, such that the tip alone cannot saturate a capacitive sensor
of the display. The size is typically between 2-3 mm but may be
larger or smaller.
According to one aspect the conductive part 13 is electrically
coupled to the tip 12. Such an electrical connection will increase
the capacitive foot print of the conductive part on the touch panel
30.
The dimensions and conductivity of tip 12 and of the conductive
part 13 are optimized so that both the housing and tip produce
capacitive foot prints 50, when used in a normal drawing situation.
A foot print 50 implies a capacitance detectable by the capacitive
touch panel. Hence, by measuring the size and shape of the foot
print 50, a change in capacitance can be registered by the
capacitive touch panel.
When the pen is held in an upright position as shown in FIG. 3a,
the sensor readout will have a circular form 50a, because in an
upright position, the tip and the conductive part are aligned above
the touch panel 30. The conductive part 13 is positioned at the
elongated body 11. In FIGS. 3 and 4 the conductive part is placed
at one end of the elongated body 11. However, the conductive part
may as well be placed apart from the tip as disclosed in FIG.
5.
When the pen is held in a normal drawing position as shown in FIG.
3b, (around 45 degrees towards the surface), the conductive part
will move in a horisontal direction in relation to the board.
However, both the tip and the conductive part will produce a
capacitive footprint. Therefore, the sensor readout of the touch
panel 30 will then have a non-circular form 50b. The pen tip will
produce signal as well as the housing and depending on angle the
effect from the housing will change. Because the touch panel can
detect items above the surface of the panel, the conductive part
will be "visible" to the touch panel. Hence, the conductive part 13
is configured such that the distortion of the screen's
electrostatic field caused by the conductive part when changing the
position of the touchpen in relation to the capacitive touch panel,
when the contact surface is kept in contact with the touch panel,
is sufficient to register a change in capacitance by the capacitive
touch panel. Position here implied both tilt and also the distance
between the body member 11 and the touch panel. Hence, the
electrostatic field of the pen may change even though the tip is
kept at the same place, i.e. the same (x,y) position at the
screens's surface. The capacitive change in then caused by the
movement of the conductive part. Hence, many different footprints
correspond to one contact point between the pen tip 13 and the
touch panel 30. These different footprints correspond to one
position of the pen 10.
Thereby, the position of the pen may be detected, because the
conductive part will generate a capacitive foot print which depends
on the position, e.g. tilt, of the pen. In use the pen would of
course often be moving. However, at a certain moment, it is then
possible to detect both the touched point of the pen (x,y) and a
value corresponding to the position. The position may be translated
to e.g. tilt or pressure, depending on the design of the pen, as
will be shown in the embodiments below.
For example, the distance between the conductive part and the
capacitive touch panel can be decreased by tilting the body member
11 as disclosed in FIG. 3b. Thereby, by measuring the form, size
and amplitude of the output signal from the capacitive sensor a
good estimate of both pen direction and tilt is possible.
FIGS. 4a to 4c discloses a pen according to another aspect of the
disclosure. In FIG. 4 the pen tip is held by a spring which lets
the tip to be retracted dependent on pen tip pressure and the force
of the spring working as an anvil against the pen tip when the pen
tip is pressed towards the spring. Because the pen tip is
retractable the sensor reading of the Z-value will increase when
the pen is pressed harder against the surface because the
conductive part 13 then comes closer to the surface. In other
words, the pen tip is movable in relation to the conductive part in
a telescopic way, i.e. the pen tip is telescopically suspended at
the conductive part. In FIG. 4 the tip 12 is held by an elastic
member such that the retraction depends on the pressure applied on
the tip and the resilience of the elastic member working in the
similar way as a springy anvil when the pen tip 12 is pressed
towards the elastic member. Hence, according to one aspect the
distance between the conductive part and the capacitive touch panel
is decreased by pushing the retractable tip into the body. When the
conductive part gets closer to the touch panel the z value of the
capacitive sensor will increase. By measuring the form, size and
amplitude of the output from the capacitive sensor a good estimate
of pen pressure, direction and tilt is possible.
According to one aspect, pen tips are interchangeable. It is also
possible to use springs with different spring coefficients to allow
different pressure sensitivity. According to one aspect, spring
pressure could also be changed through a mechanical button or screw
on the pen that allow the length of the spring in its rest position
to be changed. According to one aspect, an elastic member with
varying elasticity or resilience may be used for allowing different
pressure sensitivity. According to one aspect, an interchangeable
elastic member may also be used meaning that a softer elastic
member (with a lower resilience) may be replaced by a harder
elastic member (with a higher resilience) or vice versa. According
to one aspect, the pen tip and the elastic member may be
interchangeable as separate entities for easy adjustment and change
of the pressure sensitivity. According to one aspect, the pen tip
and the elastic member may be interchangeable together as one unit
for quick change of the pressure sensitivity depending on the need
of the user. Another way to adjust pressure sensitivity is to use
different conductive materials in the pen tip and the housing.
According to one aspect, shown in FIGS. 3a and 3b, the back of the
pen can be modelled with a single conductive ball 19 (on a isolate
housing) the readout from the end can be distinguished from the pen
tip and in term be interpreted as another pen type e.g. an
eraser.
According to one aspect, the surface of the pen housing is an
isolate to remove affect from difference of conductivity from the
hand. If the part of the pen where the user holds is insulated the
signal from the pen will be the same between different users and
thus easier to interpret.
FIGS. 5a to 5b discloses a pen according to one aspect of the
disclosure. In some situations it may be more effective to only
have a narrow rim around the housing and let the rest of the
housing be an isolate. In this case the capacitive footprint will
look like two dots 50'' instead of a non circular connected shape,
when the pen is tilted.
FIG. 6 discloses in a flowchart a method in an electronic device of
detecting the position of a touchpen used for inputting information
into the electronic device through touching of a capacitive touch
panel using a touchpen comprising an elongated body member
comprising a conductive part and a tip disposed at one end of the
body member as described above. The method is carried out within
the electronic device, but may be executed in the IC 34 of the
touch panel device as well an in the software of the electronic
device 1.
The method is initiated when contact of the tip is detected S1 at
the capacitive touch panel. The second step comprises measuring S2
a distortion of the screen's electrostatic field. This is typically
performed by the IC 34 of the touch panel device 20. The IC then
outputs touch data to the electronic device, where the further
calculations are made. As an alternative all calculations are
performed in the IC 34. The method may be executed in hardware,
software or in a combination thereof.
In practice, it is not needed to detect the tip first and then
detect the distortion of electrostatic field. The total distortion
of the electrostatic field may be used to detect the tip and the
body of the pen. This means that steps S1 and S2 may be integrated
into one step.
The final step comprises determining S3 a change in position of the
touchpen in relation to the capacitive touch panel, based on the
distortion of the screen's electrostatic field caused by the
conductive part. This step e.g. implies analysing the shape of the
capacitive field and determining the direction of the pen based on
the field. If the foot print of the conductive part 13 is detected
to the left of the point of the "touch", then it may be assumed
that the pen is leaning to the left, see FIGS. 3a and 3b.
According to one aspect the change in position is detected using
the size of the distortion of the screen's electrostatic field.
According to one aspect the change in position is detected using
the amplitude of the distortion of the screen's electrostatic
field. For example the size and amplitude may be assumed to
increase if the conductive part is brought closer to the touch
panel.
According to one aspect the disclosure relates to a computer
program, comprising computer readable code which, when run on a
wireless network node in a cellular communication system, causes
the node to perform the method as described above.
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